Process Control Research Articles

Dimensions of Posterior Implant Restorations Related to Intra-Coronal Cantilever and Occlusal Forces: An In Vitro Study.

The aim of the present study was to investigate the relation of the implant position to the implant crown and analyze the location and magnitude of bite force. The dimensions of 49 posterior implant-supported restorations were recorded in terms of: 1. implant diameter, 2. crown length, 3. crown width, 4. crown height, 5. occlusal surface of the restoration. The crown/implant height was measured and the distance between the implant center and the restoration center revealed the size of intra-coronal cantilevers. The occlusal force analysis determined the point and magnitude of loading. Correlation coefficient r was used for the statistical process and statistical control was carried out with the aid of t-test with minimum level of significance p < 0.05. - The mean crown-to-implant ratio was 0.9 and in short implants (< 10mm) the ratio was 1.28. - Intra-coronal cantilever extensions ranged from 2.1 mm to 6.35 mm depending on crown size. - Occlusal loading was identified in cantilever areas of the crown. - Implant center deviates from crown center in 71%-82% of the cases depending on site location. - Implants with non-ideal position may support a functionally occluding crown. Intra-coronal cantilevers are a critical factor to avoid clinical complications and should be taken under consideration both in the planning and fabrication phase of implant restorations.

Effect of plasma treatment on LMPAEK/CF tape and composites manufactured by automated tape placement (ATP)

Automated tape placement (ATP) process is widely used in aerospace for its advanced process control and multi-axis capabilities but faces issues like limited choice of materials and suboptimal tape consolidation. This study investigates air plasma treatment on ATP carbon fiber thermoplastic feedstock tape to address these challenges. The effects on low melt Polyaryletherketone/carbon fiber unidirectional tape (LMPAEK/CF UD tape) were analyzed. Treated and untreated tapes were used to fabricate composites and evaluated for physical, thermal, mechanical, and interfacial properties. Atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) analyses revealed surface roughness changes (on LMPAEK), extent of oxidation, and the presence of hydroxyl/carboxyl groups. Composites from plasma-treated tapes showed a 7.6% increase in tensile strength, 8% in tensile modulus, 18% in flexural strength, and 8.3% in flexural modulus. The interlaminar shear strength improved by 18.7%. Failure analysis showed untreated composites failed via inter-ply and fiber-matrix delamination, while treated composites experienced matrix cracking and fiber breakage. This study highlights atmospheric plasma treatment as a solution to ATP’s limitations, significantly enhancing LMPAEK/CF UD tape composites’ properties.

Programmable mechanical properties of additively manufactured novel steel

Abstract Tailoring thermal history during additive manufacturing (AM) offers a feasible approach to customise the microstructure and properties of materials without changing alloy compositions or post-heat treatment, which is generally overlooked as it is hard to achieve in commercial materials. Herein, a customised Fe-Ni-Ti-Al maraging steel with rapid precipitation kinetics offers the opportunity to leverage thermal history during AM for achieving large-range tunable strength-ductility combinations. The Fe-Ni-Ti-Al steel was processed by laser-directed energy deposition (LDED) with different deposition strategies to tailor the thermal history. As the phase transformation and in-situ formation of multi-scale secondary phases of the Fe-Ni-Ti-Al steel are sensitive to the thermal histories, the deposited steel achieved a large range of tuneable mechanical properties. Specifically, the interlayer paused deposited sample exhibits superior tensile strength (~1.54 GPa) and moderate elongation (~8.1%), which is attributed to the formation of unique hierarchical structures and the in-situ precipitation of high-density η-Ni3(Ti, Al) during LDED. In contrast, the substrate heating deposited steel has an excellent elongation of 19.3% together with a high tensile strength of 1.24 GPa. The achievable mechanical property range via tailoring thermal history in the LDED-built Fe-Ni-Ti-Al steel is significantly larger than most commercial materials. The findings highlight the material customisation along with AM’s unique thermal history to achieve versatile mechanical performances of deposited materials, which could inspire more property or function manipulations of materials by AM process control or innovation.

An Exploration of Alkaline Degumming in the Printing and Dyeing Process of Silk Georgette

Alkali printing was one of the traditional techniques employed for printing on silk georgette in ancient China. This study investigates two degumming methods in alkaline printing processes, namely alkaline boiling and alkaline steaming, based on the principles of Tang Dynasty alkaline printing techniques. The effects of slaked lime concentration, steam temperature, and steam duration on the degumming rate of silk georgette are studied. Alkaline boiling is found to be rapid and effective, achieving a degumming rate of 27% at 80 °C in 30 min, whereas alkaline steaming requires a prolonged process with a maximum degumming rate of less than 20% before the water reaches its boiling point. Additionally, the differences in dyeing effects at various degumming rates, and the variations in pattern clarity and detail under alkaline steaming, were compared. Although both degumming methods can achieve the desired amount of degumming rate through process control, alkaline steaming allows for integration with methods like screen printing and rotary printing, offering better control over pattern freedom and detail. The combination of these two processes can further expand the artistic expression and application of traditional alkaline printing techniques in contemporary silk degumming printing.

Removal of Residual Additive Enabling Perfect Crystallization of Photovoltaic Perovskites.

Achieving high-efficiency perovskite solar cells (PSCs) hinges on the precise control of the perovskite film crystallization process, often improved by the inclusion of additives. While dimethyl sulfoxide (DMSO) is traditionally used to manage this process, its removal from the films is problematic. In this work, methyl phenyl sulfoxide (MPSO) was employed instead of DMSO to slow the crystallization rate, as MPSO is more easily removed from the perovskite structure. The electron delocalization associated with the benzene ring in MPSO decreases the electron density around the oxygen atom in the sulfoxide group, thus reducing its interaction with PbI2. This strategy not only sustains the formation of a crystallization-slowing intermediate phase but also simplifies the elimination of the additive. Consequently, the optimized PSCs achieved a leading power conversion efficiency (PCE) of 25.95% along with exceptional stability. This strategy provides a novel method for fine-tuning perovskite crystallization to enhance the overall performance of photovoltaic devices.

Prevent Acute Chest Syndrome checklist (PACScheck): A quality improvement initiative to reduce acute chest syndrome.

Acute chest syndrome (ACS) is a life-threatening complication of sickle cell disease (SCD). The Prevent Acute Chest Syndrome checklist (PACScheck) was created to drive appropriate ordering of opioids, incentive spirometry (IS), intravenous fluids (IVF), evaluation of oxygen desaturation, and bronchodilator use. Decrease the development of ACS by 5% in a hospitalized pediatric SCD population. A multidisciplinary team conducted a quality improvement (QI) project between April 2020 and August 2021 on an inpatient pediatric hematology unit. At-risk hospitalizations were patients with SCD who did not have ACS upon hospital admission. PACScheck was implemented and weekly run charts assessed documentation. Process control (p) charts, geometric control (g) charts, and chi-square tests assessed checklist process measures pre- and post-PACScheck. G chart assessed the number of encounters between ACS events. A total of 483 at-risk hospitalizations were identified in the 12 months prior and 363 during the study period. A g chart demonstrated that fewer encounters developed ACS during PACScheck. A p chart demonstrated that IS documentation increased during PACScheck. A run chart of PACScheck documentation demonstrated a median of 100% documentation at least once per hospitalization during the last six months of the intervention. Development of ACS can be reduced by implementing a best-practices checklist (PACScheck) on an inpatient pediatric hematology unit with a multidisciplinary team.

Development of a Single Vial Mass Flow Rate Monitor to Assess Pharmaceutical Freeze Drying Heterogeneity.

During pharmaceutical lyophilization processes, inter-vial drying heterogeneity remains a significant obstacle. Due to differences in heat and mass transfer based on vial position within the freeze drier, edge vials freeze differently, are typically warmer and dry faster than center vials. This vial position-dependent heterogeneity within the freeze dryer leads to tradeoffs during process development. During primary drying, process developers must be careful to avoid shelf temperatures that would result in overheating of edge vials causing the product sublimation interface temperature to rise above the critical (collapse) temperature. However, at lower shelf temperatures, center vials require longer to complete primary drying, risking collapse or melt-back due to incomplete drying. Both situations may result in poor product quality affecting drug stability, activity, and reconstitution times. We present a new approach for monitoring vial location-specific water vapor mass flow based on Tunable Diode Laser Absorption Spectroscopy (TDLAS). The single vial monitor enables measurement of the gas flow velocity, water vapor temperature, and gas concentration from the sublimating ice, enabling the calculation of the mass flow rate which can be used in combination with a heat and mass transfer model to determine vial heat transfer coefficients and product resistance to drying. These parameters can in turn be used for robust and rapid process development and control.

Raman‐Enabled Predictions of Protein Content and Metabolites in Biopharmaceutical Saccharomyces cerevisiae Fermentations

ABSTRACTRaman spectroscopy, a robust and non‐invasive analytical method, has demonstrated significant potential for monitoring biopharmaceutical production processes. Its ability to provide detailed information about molecular vibrations makes it ideal for the detection and quantification of therapeutic proteins and critical control parameters in complex biopharmaceutical mixtures. However, its application in Saccharomyces cerevisiae fermentations has been hindered by the inherent strong fluorescence background from the cells. This fluorescence interferes with Raman signals, compromising spectral data accuracy. In this study, we present an approach that mitigates this issue by deploying Raman spectroscopy on cell‐free media samples, combined with advanced chemometric modeling. This method enables accurate prediction of protein concentration and key process parameters, fundamental for the control and optimization of biopharmaceutical fermentation processes. Utilizing variable importance in projection (VIP) further enhances model robustness, leading to lower relative root mean squared error of prediction (RMSEP) values across the six targets studied. Our findings highlight the potential of Raman spectroscopy for real‐time, on‐line monitoring and control of complex microbial fermentations, thereby significantly enhancing the efficiency and quality of S. cerevisiae‐based biopharmaceutical production.

Mechanical energy absorption capacity of the porous Ti-6Al-4V alloy under quasi-static and dynamic compression

Porous materials are very efficient in absorbing mechanical energy in different applications. In the present study, porous materials based on the Ti-6(wt.%)Al-4V alloy were manufactured with the use of two different powder metallurgy methods: i) blended elemental powder approach using titanium hydride (TiH2) as well as V-Al master alloy powders and ii) using hydrogenated Ti-6-4 pre-alloyed powder. The powder compacts were sintered with additions of ammonium bicarbonate as a pore-holding removable agent. The emission of hydrogen from hydrogenated powders on vacuum sintering and the resulting shrinkage of powder particles permitted the control of the sintering process and creation of anticipated porous structures. Mechanical characteristics were evaluated under quasi-static and dynamic compressive loading conditions. Dynamic compression tests were performed using the direct impact Hopkinson pressure bar technique. All investigations aimed at characterizing the mechanical energy-absorbing ability of the obtained porous structures. The anticipated strength, plasticity, and energy-absorbing characteristics of porous Ti-6-4 material were evaluated, and the possibilities of their application were also discussed. Based on the obtained results, it was found that porous Ti-6-4 material produced with a blended elemental powder approach showed more promising energy absorption properties in comparison with pre-alloyed powder.

Dynamic Performance Evaluation of a Five-Phases Induction Motor System controlled using Fuzzy Logic Director

The five-phase induction motor drive offers distinct benefits that enhance the motor's torque production capabilities. The proposed fuzzy logic controller is well suited for high-performance five-phase induction motor drives. This paper is discussed about a speed control strategy for a five-phase induction motor drive system using a Fuzzy Logic Controller (FLC). This controller adjusts system parameters through a rule-based fuzzy logic system, mimicking human reasoning for process control. The speed control algorithm employs indirect vector control.

Enabling tailored microstructures by hybrid directed energy deposition processing of a nickel-based superalloy

The technological advances in additive manufacturing, particularly laser based directed energy deposition (DED), revolutionized the production of complex metal components. Despite this progress, the oriented heat flux and several reheating thermal cycles can induce a strongly textured microstructure, which induces an anisotropic mechanical behavior. In addition, considerable residual stresses typically require additional post-processing. Therefore, hybrid process chains for additive manufacturing (AM) are being developed, which aim at integrating conventional post-processing into the AM process. However, a detailed investigation of thermal and mechanical effects of such hybrid processes on the mechanical properties and their interrelation is lacking. In an experimental study, we explore the integration of thermal and mechanical processing steps within the DED process chain to locally tailor microstructures and mechanical properties. Through electron backscatter diffraction measurements, we demonstrate significant microstructural changes of DED-manufactured nickel-based superalloy samples using deep rolling and laser heat treatment. A mechanical surface deformation induces microstructural misorientation leading to an increase in hardness down to substantial depth of several hundred micrometers. Additionally, the targeted management of heat input during laser heat treatment results in different grain morphologies and sizes, affecting average microhardness within a significant depth. The results demonstrate the potential for microstructural tailoring using hybrid AM process chains, while a substantial sensitivity of the microstructure to thermal and mechanical load emphasizes the importance of a precise process control. This work provides an understanding of the process-microstructure-property relationship required for developing new process pathways in hybrid AM that integrate thermal and mechanical processes into DED manufacturing.

Quality management of head and neck patient treatments using statistical process control techniques.

The treatment, planning, simulation, and setup of radiotherapy patients contain many processes subject to errors involving both staff and equipment. Cone-beam-CT (CBCT) provides a final check of patient positioning and corrections based on this can be made prior to treatment delivery. Statistical Process Control (SPC) techniques are used in various industries for quality management and error mitigation. The utility of SPC techniques to monitor process and equipment changes in our Head and Neck patient treatments was assessed by application to CBCT results from a quality-focused longitudinal study. Individuals and moving range (XmR) as well as exponentially-weighted moving average (EWMA) techniques were explored. The SPC techniques were sensitive to process changes and trends over the 12 years of data collected. A reduction in the random component of patient setup errors needing correction was observed. Systematic components of error remained more stable. An uptick in both datasets was observed correlating with the COVID-19 pandemic. Process control limits for use in prospective process monitoring were established. Challenges that arose from using SPC techniques in a retrospective study are outlined.

Application of Hydrogen Spillover to Enhance Alkaline Hydrogen Evolution Reaction

AbstractAlkaline water splitting has shown great potential for industrial‐scale hydrogen production. However, its broad application is constrained by hydrogen evolution reaction (HER) electrocatalysts, which struggle to achieve optimal current density at low overpotential. The utilization of the hydrogen spillover effect to augment the performance of HER represents a burgeoning area of research. Although previous studies mainly focused on hydrogen spillover in acidic media, the latest studies have shown that hydrogen spillover also exists under alkaline conditions, and its role in improving HER performance cannot be ignored. This review examines the mechanisms of HER under acidic and alkaline conditions, elucidating the distinctive behavior of hydrogen spillover in these environments and its influence on catalytic processes. At the same time hydrogen spillover characterization methods are systematically summarized, these technologies for understanding and control of hydrogen release process provides strong support. Finally, the recent electrocatalysts that enhance the catalytic performance of alkaline HER by hydrogen spillover effect are comprehensively sorted out and summarized. This review not only demonstrate the practical value of hydrogen spillover under alkaline conditions, but also provide new directions for future design and optimization of electrocatalysts.

The Impact of Risk Management on Project Success: A Field Study at Humanitarian Organizations in Yemen

The study aimed to determine the impact of risk management (risk identification, risk analysis, risk response and risk monitoring and control) on project success (scope, schedule, cost and quality) at humanitarian organizations operating in Yemen (HOY). The study followed the analytical descriptive approach to meet its objectives. It utilized the simple random technique to select 15 organizations representing 127 HOY and the disproportional stratified random sampling technique to target the respondents. Data was collected through a printed questionnaire from 185 respondents who have roles in managing projects at the targeted organizations. The findings showed that risk management has a significant positive impact on project success. The findings also revealed that among 4 dimensions of risk management process, risk identification and risk monitoring and control were found as the most significant influencers that impact project success at HOY. The study recommends HOY to pay more attention to project risk management to attain higher project success level that ultimately contributes to the performance improvement and sustainability of their organizations. The study also recommends conducting more studies for further confirmations to the hypothesis of the study through testing the study’s variables at industries other than HOY such as banking industries and telecommunications companies.

Integrative approach to fluorescence-based oxygen sensing in polymer optical fibers with surface plasmon resonance

This study demonstrates a technique to enhance oxygen (O2) concentration measurement by combining surface plasmon resonance (SPR) and fluorescence-based sensor on polymer optical fiber (POF). The SPR was generated using silver (Ag) and the fluorescence was generated by organic dye. Three fluorescence dyes were used, Tris (4, 7-diphenyl-1, 10-phenanthroline) ruthenium (II) dichloride ([Ru(dpp)3]2+), platinum octaethylporphyrin (PtOEP) and 5,10,15,20-tetrakis (pentafluorophenyl) 21 H,23H-porphine palladium (II) (PdTFPP). The sensor was tested in a gas chamber with different concentration level of O2. Sensitivity values for the fluorescence dyes for [Ru(dpp)₃]²⁺, PtOEP, and PdTFPP were 0.0099 a.u/%, 0.0343 a.u/% and 0.05 a.u/% respectively. When SPR was implemented, the sensitivity values for Ag/[Ru(dpp)₃]²⁺, Ag/PtOEP, and Ag/PdTFPP were 0.0589 nm/%, 0.0345 nm/%, and 0.118 nm/% respectively. PdTFPP and Ag/PdTFPP exhibit highest sensitivity in each experiment. Therefore, the further analysis for the sensing performance of PdTFPP and Ag/PdTFPP were held. As a result, Ag/PdTFPP exhibits lower limit of detection (LOD), and limit of quantification (LOQ) with 3.054 % and 9.254 %, respectively, with higher R2 of 0.9971 and lower mean standard deviation of 0.174, compared to PdTFPP 16.496 % and 49.988 % respectively, with R2 of 0.9211 and higher mean standard deviation of 2.003. This improvement can benefit researchers and professionals in medical diagnostics, environmental monitoring, and industrial process control by providing a more sensitive and accurate method for measuring O2 levels.

Acquiring better load estimates by combining anomaly and change point detection in power grid time-series measurements

In this paper we present novel methodology for automatic anomaly and switch event filtering to improve load estimation in power grid systems. By leveraging unsupervised methods with supervised optimization, our approach prioritizes interpretability while ensuring robust and generalizable performance on unseen data. Through experimentation, a combination of binary segmentation for change point detection and statistical process control for anomaly detection emerges as the most effective strategy, specifically when ensembled in a novel sequential manner. Results indicate the clear wasted potential when filtering is not applied. The automatic load estimation is also fairly accurate, with approximately 90% of estimates falling within a 10% error margin, with only a single significant failure in both the minimum and maximum load estimates across 60 measurements in the test set. Our methodology’s interpretability makes it particularly suitable for critical infrastructure planning, thereby enhancing decision-making processes.

On-Demand Coalescence of Ferromagnetic Droplets in Microchannels Using an Oscillating Magnetic Field.

Droplet-based microfluidics exhibit remarkable potential in achieving high-throughput chemical reactions with minimal reagent consumption. However, a pivotal challenge lies in the selective coalescence of droplets for precise process control, particularly when dealing with droplets of varying amounts and volumes, which are difficult to trap and coalesce due to their tiny dimensions and incessant movement. Hence, we proposed a method for on-demand coalescence of ferromagnetic droplets using an oscillating magnetic field. Experimental results show that the ferromagnetic droplets can be trapped in different positions in the microchannels according to the applied magnetic field intensity. A high-intensity pulsed amplitude of the magnetic field enables the migration of trapped droplets toward the same position, facilitating their mutual contact and interaction. By programmable modulation of the oscillating magnetic field, a controllable reciprocation of droplets in microchannels was successfully realized, which enabled us to dynamically capture, coalesce, and release two or more (≥3) droplets on demand. The integrated ferromagnetic droplet-based microfluidic platform allows contact-free, easily monitored, and on-demand coalescence of ferromagnetic droplets in microchannels, which holds promise for a wide range of applications, such as microfluidic-based drug synthesis, biosensing, reaction kinetics, and paracrine signaling, particularly.

Navigating the path to equitable rheumatologic care for underserved children with quality improvement.

The aim of this quality improvement project is to identify children with rheumatologic conditions to prevent delayed or missed diagnosis in underserved pediatric populations. Our focus is on prompt and accurate identification and subsequent treatment of rheumatologic symptoms in pediatric patients referred from Atrium Health safety-net primary care clinics that deliver care to families without private insurance, including those lacking insurance entirely. We collaborated with providers at one safety-net clinic to improve the processes of identification and subspecialty referral, resulting in an increase in the number of identified pediatric patients and referrals for these patients with potential rheumatologic disease. We used the Model for Improvement framework with rapid Plan-Do-Study-Act cycles and evaluated improvement with run and statistical process control charts. We achieved improvement, with zero referrals in the previous 5 years for the targeted population increasing to 15 patient referrals within 1 year of project initiation. Despite this increase in referrals, the rheumatology clinic was able to see all priority patients within 20 business days from referral. An awareness of concerning rheumatologic symptoms in safety-net primary care clinics, combined with the use of both visual and decision aids, allows care teams to efficiently recognize and accurately refer patients needing specialty care.

Economical management of diesel generator sets by means of MATLAB digital technologies

A numerical algorithm for optimizing the technological processes of diesel generator sets operating on various grades of fuel, implemented by means of CVX-technologies, is considered. Traditional algorithms have generally proven to be positive, but can be problematic for optimization due to the large number of variables and the nonlinearity of the model. In addition, due to the huge computational load, they can “stall” or become damaged when used to search for non-standard designs, such as asymmetric D-optimal and large-dimensional spatial structures. It is noted that an alternative to them is calculations in the CVX format, which are widespread and available for solving convex optimization problems. However, their application for the control of technological processes of energy saving in autonomous electric power complexes in transport is still limited. Based on the tools of the CVX package in MATLAB, using their usefulness and flexibility in comparison with traditional optimization methods, this paper proposes technical solutions aimed at developing energy-saving technologies for energy complexes of autonomous systems in the context of digital transformation. The application of energy saving management methods is presented in this study on the example of fuel consumption management by a group of diesel generators with different consumption characteristics of primary engines, for which optimal modes have been obtained at various options of active power consumption by the network. An example of calculating optimal modes in parallel operation of five DGA with CVX program codes is given, confirming the correctness of the proposed solutions. It is shown that the use of CVX programs in MATLAB demonstrates their usefulness and flexibility in comparison with traditional algorithms in the statistics of searching for various types of optimal approximate constructions by convex criterion for nonlinear models.

Vat Photopolymerization 3D Printing of Hydrogels Embedding Metal-Organic Frameworks for Photodynamic Antimicrobial Therapy.

Given the variability in wounds based on the underlying causes, personalized medicine and tailored care for patients with wounds are required to ensure optimal therapeutic outcomes. With the emergence of high-precision and high-efficiency photocuring 3D printing technology, there is the potential for its use in customizing precise shapes that can match complex wound sites, thereby providing better treatment for patients with wound infections. In this work, porphyrinic metal-organic framework (MOF) crystals, serving as the functional filler, were incorporated into gelatin methacrylate (GelMA) as a photocurable composite resin to investigate the capabilities of producing customizable wound dressings through vat photopolymerization 3D printing. The embedded MOF crystals allow for better control of the photopolymerization process due to photon competition with the photoinitiator, enabling the precise printing of complex structures. In addition, these crystals impart photothermal and photodynamic capabilities to the printed object. The antibacterial assay confirms the potent photothermal and photodynamic bactericidal properties of the printed GelMA/MOF hydrogels. The hydrogel with the highest MOF content exhibited over 99.99% antibacterial efficiency against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli after 30 min of light exposure (∼30 mW/cm2, λ ≥ 420 nm). Simultaneously, hemolysis and cytotoxicity evaluations validated their excellent biocompatibility. The findings presented here introduce a strategy for integrating photosensitive MOF and 3D printing to fabricate size-adjustable photothermal/photodynamic monoliths and patches, opening perspectives toward personalized treatment for wound management.